1988-1995 Mercury Force 5HP Outboards Service Manual, 90-823263 793, Page 199Get this manual
c REMOVING GEAR HOUSING
A WARNING
Always disconnect spark plug lead to prevent accidental starting of motor1Drain gear housing Remove drain plug (A) and washer from starboard side of gear housing Remove "vent" screw (8) and washerDrain gear housing grease into suitable contai ner, oz(0.12 L) capacity or greaterProbe drained gear lube with magnetSteel shavings indicate possible abnormalwear in gears or shifting mechanismLoosely reinstall drain plug with washer and "vent" screw with washer